Developing efficient catalysts for photocatalytic hydrogen evolution and pollutant degradation is one of the most ideal methods to address energy and environmental pollution issues. To address the challenges of energy crisis and environmental issues, a hollow spherical g-C3N4/Mn0.25Cd0.75S (HCNS/MCS) heterostructure was constructed and characterized. The unique morphology and appropriate band gap of the hollow carbon nitride sphere (HCNS) make it a promising photocatalytic material. The growth of Mn0.25Cd0.75S solid solution on HCNS enhances the spatial separation of photo-generated charges at the HCNS/MCS interface, thereby promoting electron transfer and reaction kinetics. Under visible light irradiation, the HCNS/MCS exhibited the highest H-2 production activity (31.34 mmol center dot g(-1)center dot h(-1)), which was 2.8 times that of pure MCS and 224 times that of pure HCNS. Moreover, the HCNS/MCS photocatalyst achieved a removal rate of 94% for tetracycline within 180 min under visible light, involving the center dot OH and center dot Oz radicals and following the proposed type-II mechanism. This work contributes to the design of highly efficient photocatalytic materials with synergistic effects for photocatalytic hydrogen evolution and organic pollutant degradation.

The conversion of the greenhouse gas CO2 represents a pragmatic and environmentally friendly approach. However, the substantial energy demands of the reaction hamper its widespread application. Here, we designed an efficient catalyst prepared by Ce-MOF and ZIF-67 precursor, namely Co/CeO2, for photothermal CO2 methanation under light and auxiliary heating. CeO2 synthesized by Ce-MOF has a good structure and abundant oxygen vacancies, meanwhile, Co has abundant active sites and strong adsorption capacity and is well-dispersed on CeO2. As a result, the catalyst exhibits high CH4 yield of 885.27 mmol center dot g- 1 center dot h-1 and CO yield of 24.5 mmol center dot g- 1 center dot h-1. Moreover, it has good selectivity and catalytic durability. Through the analysis of the reaction pathway under the conditions of photothermal catalysis, the hydrogenation reaction of formate can efficiently generate CH4 and H2O due to the promotion of hot carriers. This work demonstrated the advantages of photo-thermal co-catalysis and provides a potential strategy for efficient CO2 reduction.

Photothermal catalytic CO2 reduction can combine photocatalysis and thermal catalysis by using full-spectrum solar energy to convert CO2 into high value-added chemicals. This can effectively alleviate the problems of excessive CO2 emissions and thermal catalytic energy waste. In this paper, a novel catalyst was prepared using Ce-MOF as a precursor to generate Cu/Ni/CeO2 for efficient reduction of CO2 to CO by hydrogenation. Due to the rod-like structure of CeO2 and the high dispersion of Cu and Ni nanoparticles, 10

Constructing heterojunctions for efficient charge separation is a crucial method to boost photocatalytic activity. Initially, zeolitic imidazolate framework-8 (ZIF-8) nanoparticles were synthesized in situ on the surface of cadmium sulfide (CdS) nanoflowers, creating a novel ZIF-8/CdS composite material. Subsequently, a ternary Ni2P/ZIF-8/CdS composite was fabricated for photocatalytic hydrogen production and pollution reduction. The optimally obtained Ni2P/ZIF-8/CdS composites showed excellent photocatalytic efficiency and structural sta-bility under simulated solar light irradiation. The hydrogen production rate of Ni2P/ZIF-8/CdS composite was 21.05 mmol h1 g1. Additionally, Ni2P/ZIF-8/CdS degraded malachite green (MG) with 99% efficiency. It was found that the proximity of sulfides to porous MOFs accelerated the separation of light-induced charges. Nickel phosphide (Ni2P) played a vital role in photocatalytic reactions, serving the dual function of capturing photo-generated electrons and accelerating separation of photogenerated carriers. Mechanistic and characterization studies revealed that constructing heterojunction between CdS and ZIF-8 could promote photogenerated carrier transport, enhance the separation efficiency of photogenerated carriers, ultimately improving the photocatalytic hydrogen production performance and degradation efficiency.

Defect engineering and the high index surface (HIF) can be regarded as two effective methods to tuning the microstructure of catalysts and photocatalytic activities. So far, the integration of the synergistic effects of ox-ygen vacancies and HIF advantages into semiconductors to enhance photocatalytic performance has received little attention. Herein, Black In2O3_x/In2O3 with oxygen vacancy and exposed (321) surface active crystal plane has been synthesized as excellent photocatalysts via a facile method. The catalysts of Black In2O3_x/In2O3 can reach the highest photocatalytic hydrogen evolution rate (1046 mu mol h_ 1 g_ 1) and degradation efficiency of MB (0.017 min_1) with 120 min, respectively. As a special phase junction, Black In2O3_x/In2O3 could effectively boost the separation and transfer of photogenerated charges because of unique defect homojunction micro-structure resulting in exposing abundant photocatalyst redox active sites. The experiment characterization and density functional theory (DFT) calculations can further employ to unveil mechanism of enhanced hydrogen evolution reaction (HER) activity. It is obvious that enhanced HER activity was attributed to synergy of oxygen defect and exposed (321) surface active crystal planes due to electron distribution and lower Gibbs free energy of H adsorption. This work might open up new avenues to integrate exposed facets and oxygen vacancy for enhancing the photocatalytic hydrogen evolution with renewable energy sources and environmental remediation.

Industrial pollution leads to serious air pollution, which has an enormous impact on the earth's environment. Converting greenhouse gas carbon dioxide (CO2) into value-added fuels or chemicals, such as carbon monoxide (CO), methane (CH4) and methanol (CH3OH), can effectively improve the earth's atmospheric environment. Photocatalysis and thermal catalysis are the main catalytic methods to convert CO2, but their disadvantages are high energy consumption and low conversion rate. As a new type of catalysis, photothermal catalysis, which combines photocatalysis and thermal catalysis and takes into account the advantages of both catalysts, has been widely studied and has a broader research prospect in recent years. Previously, there were relatively few reviews that classified photothermal catalysis based on different principles. In this review, photothermal catalysis is divided into photo-assisted thermocatalysis, thermal-assisted photocatalysis and photothermal co-catalysis. This article collects representative studies on photothermal catalysis in recent years and categorizes them into photo-assisted thermocatalysis, thermal-assisted photocatalysis and photothermal co-catalysis. By analyzing and comparing their reaction mechanisms and effects, it can provide readers with a more comprehensive and clear understanding of the differences in these three types of catalytic methods. Moreover, this work summarizes the general types of catalysts for each type of catalytic method, providing a comprehensive and intuitive understanding for subsequent researchers. Among them, MOFs, LDHs, Mxenes and other catalysts are used for the reduction of CO2 by H2, CO2 by H2O to generate CO, CH4 and other products. Finally, this review looks forward to and reflects on the future development and challenges of this new type of photothermal catalysis.

Chitosan has received widespread attention as an adsorbent for pollutants because of its low cost and great adsorption potentials. Chitosan has abundant hydroxyl and amino groups that can bind heavy metal ions. However, it has defects such as sensitivity to pH, low thermal stability, and low mechanical strength, which limit the application of chitosan in wastewater treatment. The functional groups of chitosan can be modified to improve its performance via crosslinking and graft modification. The porosity and specific surface area of chitosan in powder form are not ideal, therefore, physical modification has been attempted to generate chitosan nanoparticles and hydrogel. Chitosan has also been integrated with other materials (e.g. graphene, zeolite) resulting in composite materials with improved adsorption performance. This review mainly focuses on reports about the application of chitosan and its derivatives to remove different heavy metals. The preparation strategy, adsorption mechanism, and factors affecting the adsorption performance of adsorbents for each type of heavy metal are discussed in detail. Recent reports on important organic pollutants (dyes and phenol) removal by chitosan and its derivatives are also briefly discussed.

A series of tetra-substituted metal phthalocyanine-multi-walled carbon nanotube composites ([4a (OPh-p-Cl)MPc]-MWCNTs) were fabricated, which were used to effectively catalyze the oxidation of benzyl alcohol. The as-prepared composites were characterized by ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, scanning electron microscope and transmission electron microscope. In order to improve the catalytic activity, the effects of solvent, amount of oxidant, amount of catalyst, temperature and reaction time on catalytic oxidation of benzyl alcohol to benzaldehyde were studied. It can be found that the Cu phthalocyanine based composite [4a (OPh-p-Cl)CuPc]-MWCNTs have the best catalytic activity in the oxidation of benzyl alcohol. The conversion rate of benzyl alcohol can reached 70%, the selectivity of benzaldehyde was 87%, and the yield of benzaldehyde can reached to 61%. In addition, a possible mechanism for the enhanced catalytic activity of the optimized [4a (OPh-p-Cl)MPc]-MWCNTs has been discussed.

Photocatalytic CO2 reduction into renewable fuels by sustainable and clean solar energy can be considered as an ideal option to decrease the atmospheric CO2 level and fulfill the energy requirements. Layered double hydroxides (LDHs) with high surface area, tunable composition as well as exposed active sites have received enormous attention for photocatalytic CO2 reduction. Herein, a novel NiAl-LDH/Ti(3)C(2)Tx nanosheet (NiAlLDH/TNS) with a core-shell structure was synthesized via an in situ hydrothermal method, and 2D NiAl-LDH coupled with the 2D Ti(3)C(2)Tx nanosheet to form a Schottky junction can suppress the back-diffusion of electrons and facilitate the transfer of charge carriers. Benefiting from the feature, the optimized sample with the additive Ti(3)C(2)Tx amount of 75 mg (NiAl-LDH/TNS-75) has the photocatalytic CO2 reduction conversion rate of CO (2128.46 mu mol h(-1) g(-1)) with the selectivity of CO (90.2%) under visible-light irradiation, which is about 8.6 times higher than that of pristine NiAl-LDH. This work provides a new insight into the construction of novel 2D semiconductor photocatalysts.